Thread-end clamping device



Sept. 19,1944. c, U, OLSON 2,358,731

THREAD-END CLAMPING DEVICE Filed June 5, 1942 IN VEN TOR.

Cfzarls Z Olson: I

Patented Sept. 19, 1944 UNITED STATES PA I NT FEE Q THREAD-END GLAMPINGDEVICE Charles U. Olson, Evanston, Ill. f g f Application June 5, 1942,Serial No; 4455878 2 claims; (01.1'12-252) 1 The present inventionrelates to a thread-end- 'clamping device adapted for use in connectionwith a sewing machine whereby unintentional withdrawal of the thread endfrom the eye of the needle due to accidental movement of the thread in adirection away from the needle may be effectively controlled withoutimpairingthe free feeding of the thread to the needle as required by thesewing operation;

It is a further object of this invention to pro-' claimed andillustrated in the accompanying drawing:

Fig. 1 is a fragmentary elevation showing the present thread endclamping attachment in cp erative position on the frame of aconventional sewing machine; in the full lines the presser foot andpresser foot lever are shown with the parts positioned as when inthread-clamping position and in dotted lines with the parts positionedas when in thread-releasing position.

Fig. 2 is an enlarged detail View of the present attachment showing theposition of the parts when the same are in thread gripping position.

Fig. 3 is a similar view showing the position of parts when the threadis in released relation and being fed to the needle during sewing.

Fig. 4 is a sectional View on line 44 of Fig. 1.

Fig. 5 is a detail view taken on line 5-5 of Fig. 4.

The thread-end clamping mechanism contemplated by this invention ispreferably mounted on the sewing machine head portion or frame in whichthe needle mechanism and the presser foot shaft operates. 7

Reference being had more particularly to the drawing, |0 designates asupporting member or plate having an opening near an edge thereofthrough which the member l0 may be attached to the side of the sewingmachine head by the usual screw fastening at the lower limits of a plateusually employed to enclose the needle and presser foot mechanism in themachine head. The upper portion of the plate I0 is preferably offsetoutwardly of its lower portion so as to permit disposal of the upperportion of the plate III on the machine head plate I above the shoulderat the lowerlimits of said platen and yet dispose" the lower part 01"theplate ID in a verlGYCtILl'plarie in proximityto the path of movementof the needle l8. 7

Secured to the plate H] are a pair of eyes I5 and I6 through which thethread n is arrange to travel lengthwise of the plate Ill in a pathoblique to the path of the needle l8. Intermediate the eyes I5 and 16"is a cylindrical member 23 mounted for rotation about a'pivot 24 aboutwhich the thread I1 is adapted to be drawn bent in its path between saideyes l5 and l6. The thread I1 is preferably ar'range'd to contact thesurface of the member 23 through an arc of sub-;

stantially degrees by means of a bearing or cylindrical member 20projecting from the plate Ill just below the limits of theuppe r portionof the plate 'H] and a similar bearing 20 projecting from the plate I0just below the cylindrical member 23. The member 23 is so arranged withrespect to the pivot 24 that its center of gravity is below the pivot 24whereby the member 23 is adapted to rotate by gravity toward a positionin contact with the portion of the thread ll in engagement with thebearing 2| therebelow. Ac-

oordingly, movement of the thread IT in a direction away from the needlel8 will cause the thread H to exert suflicient frictional contact withthe member 23 as to tend to drive the member 23 into closer clampingengagement with the thread I! engaging the bearing 2|, to positivelylimit further movement of the thread in a direction away from the needlel8.

Operation of the member 23 in a direction away from the thread I!engaging the bearing 2| to permit release of the thread I! for movementtoward the needle I8 is brought about upon initial movement of thethread IT in a corresponding direction due to the frictional contactprovided between the thread I1 and the member 23 which tends to drivethe latter in a movement away from the bearing 2|.

Due to vibration set up in the frame of the sewing machine during sewingwhereby unintentional movement of the member 23 into clamping engagementwith the thread sometimes occurs, it is desirable to provide means forpositively maintaining the member 23 in a position clear of the bearing2| during sewing operations. To this end the plate I0 is provided with aslot 32 in which a pin 3| projecting from the bearing or member 23isadapted to establish limits for rocking movementof the member 23. Thepin 3| is so extended as to intersect the path of a lever 30 mounted forpivotal movement on the reverse side of the plate I!) whereby the lever30 may be operated to raise and hold the pin 3| in a limited positionwith respect to the slot aforesaid and thereby maintain the member 23away from the bearing 2|. Operation of the lever 30 is obtained througha leaf spring 35 anchored to the lever 30 and preferably projectinglaterally into the path of a suitable lug or projection carried by thepresser foot bar of the sewing machine. As shown in the drawing, the lugmay take the form of a conventional cutter blade 36 mounted foradjustment on the presser foot bar.

Thus when the presser foot is in idle or raised position the blade 36 islifted to a position clear of the leaf spring 35 so as to permit themember 23 to operate by gravity to assume a thread clamping position,and when the blade 36 is lowered through lowering ofthe presser footshaft and presser foot into operative or sewing position, the blade 36engages the spring 35 to resiliently hold the pin 3| against the edge ofthe slot to limit or bias the member 23 into a position clear from thebearing 2| so as to release the thread l'l for movement toward theneedle l8.

from its spirit and scope as set forth in the ap-;.

pended claims.

What is claimed is:

1. In a thread-end clamping .device adapted for attachment to the frameof a sewing machine,

25 The arcuate thread engaging surfaces of the a supporting member,means associated with said supporting member through which a strand ofthread is trained to travel in a predetermined path including a bearingpresenting a threadengaging surface of convex cross-sectional contour;means cooperating with the thread portion in engagement with saidbearing to prevent movement of the thread in a direction away from aneedle associated with said machine including a member pivotally mountedon said support for movement on said support toward and away from saidbearing and about which said thread strand has contact throughout an arcof substan tially 180 degrees, and means through which said member isbiased to a position away from said bearing including a resilient leveradapted to coact with a projection on the presser foot shaft of saidmachine when the presser foot is in work position, V

'2. In a thread-end clamping device adapted for attachment to the frameof a sewing machine, a supporting member, means associated with saidsupporting member through which a strand of thread is trained to travelin a predetermined path including a bearing presenting a thread engagingsurface of convex cross-sectional contour, means cooperating with thethread portion in engagement with said bearing to prevent movement in adirection away from a needle associated with said machine including acylindrical member mounted for pivotal movement on said support towardand away from said bearing and biased by gravity for movement towardsaid bearing, and means actuated by the presser foot control associatedwith said machine for eifecting movement of said cylindrical member awayfrom said bearing.

CHARLES U. OLSON.

